High-Temperature Oxidation and Wear Behavior of (Fe,Cr)Al Intermetallic Compound and (Fe,Cr)Al-Al2O3 Nanocomposites

In the current study, oxidation and wear resistance of FeAl and (Fe,Cr)Al intermetallic compounds as well as (Fe,Cr)Al-5%vol Al2O3 and (Fe,Cr)Al-10%vol Al2O3 nanocomposites were investigated. Ball-milled powders were hot-pressed at 5.5 GPa and 1600 °C for 15 min in order to produce the bulk samples. The cyclic oxidation test was performed at 1100 °C for 100h. High-temperature wear tests were conducted at 400 °C with loads of 20 N in sliding speed and sliding distance of 0.1 m/s and 500 m, respectively. Furthermore, the nano-scratch tests were performed in single-direction as well as pass and return modes with a maximum load of 20 mN. Results showed that the (Fe,Cr)Al intermetallic compound had superior oxidation resistance with the lowest kp value at the same oxidation time. The improved oxidation performance of (Fe,Cr)Al intermetallic compound compared to (Fe,Cr)Al-Al2O3 composites can be due to the presence of more Al in (Fe,Cr)Al sample. According to the nano-scratch test, (Fe,Cr)Al-10%vol Al2O3 nanocomposite (with H/E ratio of 0.036) had the best wear resistance. On the other hand, nanocomposites containing 5% and 10% of Al2O3 had the lowest friction coefficient (≈ 0.6 and 0.3, respectively). The main wear mechanism for the FeAl compound was adhesive wear, while, delamination was the main mechanism for samples containing Al2O3 nanoparticles. Although the formation of Al2O3 reinforcement nanoparticles somewhat decreases the oxidation resistance, it also resulted in significant overall improvement in the wear behavior.